Evans Cycles is celebrating its 90th anniversary this year and in the spirit of that, we decided to look back on the last 90 years and relive important moments and talk about brands, events, partners. This post is part of a series of posts, you can check out the other articles here.

While there are many folding bike brands around and I have ridden many of them, I’ve always been fascinated by the brilliant folding mechanism of Brompton bikes. So when I received the invitation to the Brompton factory a couple of weeks ago, I became very excited by the chance to have a peek behind the scenes.
The factory is near the Kew Bridge tube station, a surprisingly central location for a bicycle manufacturing company – brownie points for anyone who can name a big bicycle company that doesn’t produces its bikes in the Far East. After a quick introduction and a short presentation, the most important and most fun part of the day arrived: we were to be shown around the factory! To make sense of the lot of phases a Brompton goes through, we vaguely followed the actual manufacturing process and I’ll follow that process, too now.

First, the steel tubes arrive, mainly from Spain. They have to comply to very strict parameters and they are constantly tested to make sure that the delivered tubes are indeed what they are supposed to be. While certain parts can go immediately to brazing, other parts, like the top tube of the frame need some work and are bent and modified by massive machines.

Once everything is prepared, the prepared tubes and other bits get to the brazers. One might think how hard brazing could be, but that couldn’t be further from the truth. It takes at least two years to learn the basics of brazing and to become a decent brazer, but you need at least another 3-4 years before one becomes a really good brazer. The quality of the brazing on the bikes are a good indication how seriously it is taken at Brompton. Whether you got pissed during the weekend or just have a bad day, the brazings still need to be perfect and they try everything to keep that very high quality steady.

There are certain parts of the process that are done by machines, mainly because technological reasons. The hinge below the stem is brazen by a machine as the bottom bit of the hinge needs to be heated to very high temperatures, therefore it would be very hard for humans to perform the same task to the same standards as a machine’s.
Once all the different parts of the frame a brazen together, they are put into this giant tumble drier and those little rocks remove any unevenness from the surface of the metal.

Once all the frames are ready, they are shipped to Wales to have them painted. Painting at this scale requires insane amount of spaces, so it makes more sense to let a specialist do the job. The two-phase painting starts with degreasing the frames and then powder coating. So when you fold your Brompton and look into the tubes, that rust-coloured thing inside the tube is not rust but the protective acid coating. After the painting, all frames are taken back to London and the assembly of the bikes begin.

The assembly happens on the other side of factory, separated by a vast storage section that contains all imaginable parts to a Brompton bike. The beauty of this whole process is that while the customers have almost endless ways to customise their Bromptons, the actual customisation only happens on the assembly-side of the factory, they use the very same frameset for each and every bike, thus keeping the brazing phases fairly simple (from this aspect only, of course).

The assembly happens in batches, each batch contains six bikes, the frames are loaded onto a rolling rack. It goes through different workstations, where the different bits and bobs are put on the bikes. A data sheet accompanies every bike that serves two purposes. Firstly, the workers know what the specifications of the bike are and assemble it accordingly. Once they are done, they stick a little bar code on the data sheet, therefore each and every bike’s “birth” can be tracked: who put the pedals on, who tightened the a bolt, etc. It serves a very important purpose: workers are more responsible for the work their doing and consistent problems can be found. These errors are often not caused by the workers but when a tool gets too worn and starts to produce subpar results. The tracking helps to identify these potential problems.

Once the bike is assembled, it goes through one final inspection, whether everything worked fine, all bolts were tight and everything was setup properly – then it gets boxed. However, every 50th bike goes to the quality assurance room to be tested. Sometimes the frameset goes into a machine that applies a certain amount of pressure and they check the effects. Often, they want to measure how precise the brazing is, as the tolerance is extremely small so that the folding works perfectly. Up until recently, they used manual methods to measure the frames which is very time consuming, but Brompton recently invested into a machine that makes the same job way faster, allowing the engineers to have a better understanding (much faster as well) how precise the manufacturing process is and whether the final products comply the standards.

The factory can produce roughly 28 000 bikes a year and quite interestingly, 2/3 of these bikes find their owner outside the UK. We often hear from our stores that they can’t get enough Bromptons, so I asked whether they would have been able to manufacture more bikes. It turned out that the bottleneck in the process is with brazing – it’s very hard to find good and skilled brazers, but certain future developments that would allow automatise further aspects of the brazing, thus allowing them to produce more bikes.

After the tour, we went back to the meeting room and were indulged with further details of product development, future plans and a very nice lunch. The electronic Brompton is still almost a year away, but the first prototypes should be ready in a couple of months. The motor is planned to be in the front hub and the whole bike should weigh slightly more than 15kg – I guess the first test rides will decide how that fairly heavy front will work in practice.

One of the early Bromptons - the desing wasn't as neat as it is nowdays

It was a long but very interesting day and I’ve found especially fascinating how passionate everybody was about the product: not just the top brass but the workers or the back office staff, too, and I think this passion shines through the bikes. I think I’m going to spend some time with the custom Brompton configurator…

If you would like to custom configure your dream Brompton, just get in touch with our contact centre or visit a local store where staff can provide you with the options and place an order with the factory.